Thermoelectric device



Jan. 10, 1933. KLQPSTEG 1,893,748

THERMOELEGTRIC DEVICE Filed Oct. 11, 1928 Patented Jan. 10, 1933 PAUL E.KLOPSTEG, OF CHICAGO, ILLINOIS, ASSIGNO R TO CENTRAL SCIENTIFIC COMPANY,OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS THERMOELECTRIC DEVICEApplication filed October 11, 1928. Serial No 311,765.

The principal object of this invention is to provide a device that willgenerate thermoelectric currents of considerable amperage and, whenproperly associated with a core,

will develop powerful magnetic forces.

Selected embodiments of the invention are shown in the accompanyingdrawing, "in which Fig. 1 is a sectional view through a thermoelectricmagnet;

- Fig. 2 is a perspective view of the thermocouple shown in Fig. 1;

' Fig. 3 is a sectional view on the line 33 of Fig. 1;

Fig. 4 is a perspective view similar to Fig-2,illustrating a variantform; and

Fig. 5 is a plan view with parts broken away, illustrating anothervariant form.

I am aware, however, that the invention may be embodied in other formswithout departing from the spirit or essential attributes thereof, andput to a variety of uses, and therefore desire that the specificillustrations and correspondingly specific description be considered asillustrative only and not restrictive, reference being had to theappended claims for the scope of the invention.

The thermo-couple illustrated in Figs. 1, 2 and 3 includes a thick rodof metal, having suitable thermo-electric' properties relative to someother suitable metal, bent to form a sub-- stantially circular loop orcoil 10, with the parallel portions 11 lying close together to form aneck, and it will be of no particular detriment to have them in contact.Beyond these portions 11 there are inclined portions 12 leading to otherparallel portions 13. beyond which one end portion of the rod is bentdownwardly. as indicated at 14. and the other laterally, as indicated at15. The other element of the thermo-couple is a bridge formed by a thickrod 16 of the other metal. having suitable thermo-electric propertiesrelative to the first, soldered between the parallel portions 13.

In Fig. 1 such a couple is fitted to a base block 17 of magneticmaterial having an annular groove 18 extended through the side of theblock at 19. A set screw 20 is provided to clamp the circular loopwithin the groove.

At the bottom the block 17 is equipped with an eye 21 for cooperationwith a hook 22 attached to a weight 23.

Above the block 17 there is a cooperating block 24 of similar material,equipped with '55 an eye 25 cooperating with a hook 26 by which theentire apparatus may be suspended.

In this particular embodiment the long rod of the couple is of copperthree-eighths inch square, and the short rod is three-eighths 6 inch byfive-eighths inch in cross-section and composed of an alloy of sixty percent to seventy per cent copper, and'fort per cent (40%) to thirty percent (30 nickel. The rods are connected by hard sol- 65 der. The blocks17 and 24 are Norway iron three inches in diameter, and the groove 18 isapproximately seven-sixteenths inch wide.

In operation the block 17 with the weight 23 is temporarily supportedwhile a Bunsen 7 the magnet will then sustain approximately 200 pounds.

The selection of metals and proportions of parts above described make avery satisfactory device of extreme simplicity which can be put in thehands of inexperienced students without danger of its being injured.Similar embodiments can also be put to a variety of uses whererobustness and dependability are required.

In the form shown in Fig. 4 the end portions 14 and 15 have beenomitted, and the parallel portions 13 are equipped with cups 27 solderedthereto; and in operation one of the cups may be filled with relativelyhot liquid and the other with a relatively cool liquid. The purpose ofsuch arrangement is to enable bismuth, which has a comparatively lowmelting point, to be substituted for the alloy of copper and nickelwhich spans the gap between the end portions 13 of the copper coil 10.By using a liquid at the hot junction the boiling point of which is lessthan the melting point of bismuth, there can be no possibility ofdamaging the device by 5. melting of the bismuth. It is of courseunderstood that bismuth is preferable to the alloy of copper and nickelin some instances because of the reduction in cost and increase ofelectromotive force.

It may be noted, however, that when bismuth is soldered to copper thejoint is composed of an alloy of tin, lead and bismuth, which has amelting temperature somewhat lower than bismuth.

In Fig. 5 the end portions 28 of the long rod of the couple are drilledat 29 and fitted with hose nipples 30, whereby steam or other hot fluidmay be applied to one end and a cooling fluid may be applied to theother. By such a structure relatively great temperature differences maybe produced in the junctions with corresponding increases inthermo-electromotive forces, thermo-electric currents and magneticeffects.

I claim as my invention 1. In a device of the character described, athermo-electric couple comprising a circular'loop of one metal havingthe end portions thereof connected by a dissimilar metal, and a magneticcore surrounded by said loop.

2. In a device of the character described, a

rod of one metal bent to form a: circular loop with its end portionsextended laterally and spaced apart, a short bar of dissimilar metalconnecting the-end portions, and a magnetic core in the loop.

3. In a device for demonstrating thermoelectromotive force, a base blockof material capable of being magnetized and having a flat face providedwith a continuous groove therein to form a core and shell of a magnet,an armature block having a fiat face to cooperate with the flat face ofthe base block, and a thermo-electric circuit comprising a singlethermo-couple located at one side of,

but adjacent to the base block, a coil within said groove, and aconductor extending through said shell and connect ng the couple withsaid coil, all parts of the thermo-electric circuit being of such greatthickness and minute resistance that the single couple can produce highamperage within the circuit. 4. In a device for demonstratingthermoelectromotive force, a base block of magnetic material having aflat face provided with a circular groove, a thermo-electric circuitcomprising a coil located in the groove and connecting a thermo-couplepresenting a hot junction at one side of the base block and a block ofmagnetic material having a fiat face engaging the flat face of the base,all parts of the thermo-electric circuit being of great thickness andminute resistance whereby a single thermo-couple can produce highamperage.

eeame 5. In a device for demonstrating thermoelectromotive force, a baseblock of magnetic material having a fiat face provided with asubstantially continuous groove therein, a

low resistance coil of metal in the groove with k the end portionsextending to the exterior of said block and connected with athermocouple, and a cooperating block of magnetic material having a flatface engaging the flat face of the base block.

6. In an experimental device for demonstrating thermo-electromotiveforce, a base block, a core extending outwardly from said block, andprovided with a smooth fiat face, said core being capable of beingmagnetized, an armature block of magnetic material having a smooth flatface for cooperating with the'fiat face of said core and a thermo-couplehaving one of its junctions located outwardly from said core, saidthermo-couple comprising a coil of conducting material of low resistanceextending about said core, said coil being of large cross sectional areathereby offering minute resistance to the flow of electricity throughthe same whereby when the hot junction of said thermo-couple is heated acurrent of high amperage will flow through said coil for magnetizingsaid core for attracting said armature.

7. For use in generating thermo-electricity, a closed electrical circuitincluding rods of dissimilar metal having thermo-electric propertiesrelative to each other, said circuit being characterized by having alarge cross sectional area at any point in the circuit rela tive to thespecific electrical resistance of the metal at that point so that thecircuit as a whole offers low resistance to the passage of current, oneof the junctions of the dissimilar metals being adapted to be heated toa relatively high temperature to cause a current of high amperage andlow voltage to flow through the circuit, a portion of said circuit beingin the form of a loop.

8. In a device of the character described, a thermo-electric couplecomprising a closed electric circuit, a portion of which is in the formof a circular loop,'said circuit including dissimilar metals having ajunction spaced from the loop and adapted to be heated to a relativelyhigh temperature to cause' a current to flow through the circuit, saidcircuit being characterized by having a large cross sectional area atany point in the circuit relative to the specific electrical resistanceof the metal at that point so that the circuit as a whole offers lowresistance to the passage of current. v

9. In a device of the character described, a thermo-electric couplecomprising a closed electrical circuit, a portion of which is in theform of a circular loop, said circuit including dissimilar metals havinghot and cold junctions spaced from each other, means for passing acooling liquid in heat exchange relation to the cold junction so thatwhen heat is applied to the hot junction, a current will flow throughthe circuit, said circuit being characterized by having a large crosssectional area at any point in the circuit relative to the specificelectrical resistance of the metal at that point so that the circuit asa whole oflers low resistance to the passage of current.

In testimony whereof I aflix my signature.

PAUL E. KLOPSTEG.

